Gases and gas mixtures used in industry, science and photography, as well as in agriculture, horticulture and forestry, namely, acetylene, argon, carbon dioxide, oxygen, nitrogen, hydrogen, gases for welding, helium, neon, krypton, xenon, methane, ethane, butane not for use as fuel, ethylene, propane not for use as fuel, propylene, hydrocarbon gases, ammonia not for cleaning purposes, chlorine, hydrogen chloride, nitrogen oxide, sulphur dioxide, sulphur hexafluoride, hydrogen sulphide, carbon monoxide, refrigerant gas for use in industrial cooling systems, and nitrous oxide for industrial use, all of the forgoing gases being types of technical gases, high purity gases, high purity gas mixtures, laboratory gases, test gases, and test gas mixtures, and including all the aforesaid in liquefied and dissolved form

Gases for medical purposes